1. Field of the Invention
The present invention relates to a battery housing structure which is used for an electronic device driven by a button-type battery.
2. Description of the Related Art
There have been commercially provided a number of portable electronic devices such as an electronic note driven by one of more button-type batteries. Hereinafter, the term "battery" means a button-type battery. Such an electronic device normally has a battery housing structure in itself.
A battery housing structure known by the present inventor will be described below.
On a case of the electronic device are arranged a first battery holding portion for holding a first main battery, a second battery holding portion for holding a second main battery, and a third battery holding portion for holding a back-up battery. The first and second main batteries are served as a main power source of an internal circuit included in the case of the electronic device. The back-up battery is served as an auxiliary power source.
The first and second battery holding portions for holding the main batteries are independent of the third battery holding portion for holding the back-up battery so that the main batteries can be held or picked out independently of the back-up battery. It means that both the main batteries and the back-up battery are allowed to be removed from the first and second battery holding portions and the third battery holding portion, respectively.
The first and second battery holding portions include a first terminal and a second terminal, respectively. The first and second terminals are respectively coupled to each one terminal of the first and second main batteries.
The first and second main batteries are repectively held in the first and second holding portions so that each one terminal of the first and second main batteries is coupled to the corresponding first or second terminal. The opposite terminals of the first and second main batteries are pressed by a first lid, and the first lid is fixed on the case by using a vis.
The first lid is compossed of a conductive material so that the first lid serves as connecting the first and second main batteries with each other.
The third battery holding portion for holding the back-up battery has a circular concave portion for holding the back-up battery. Around the concave portion are formed a first through hole and a second through hole. The first and second through holes are opposite to each other with respect to the concave portion.
A circular lid, that is, a second lid is formed to mate to the concave portion. On the periphery of the second lid are formed a first fixing pawl and a second fixing pawl. The first and second fixing pawls are respectively fixed to the first and second through holes by moving the pawls in the peripheral direction.
The second lid has a groove to be engaged with a coin or a minus driver. With the coin or minus driver being fitted in the groove, the second lid is rotated so that the back-up battery and the second lid are fixed on the case.
In exchanging the first and second main batteries and the back-up battery, however, the known battery housing structure as described above requires the annoying steps of temporarily removing the vis and the first and second lids from the case, mounting new first and second main batteries and new back-up battery on the corresponding battery holding portions, and then mounting the first lid, the vis, and the second lid on the case. Further, this battery housing structure makes it possible for a user to inadvertently mount the first lid, the vis and the second lid on the case, even in case the first and second main batteries and the back-up battery are not mounted.
As another disadvantageous matter, the first and second battery holding portions are formed independently of the third battery holding portion for holding back-up battery. Hence, the first and second main batteries and the back-up battery may be removed at a time, resulting in increasing the possibility of losing the data stored in an internal memory of the electronic device.